Tired of paying fees to cash in your frequent flyer miles, or not being able to spend them at all? Maybe what you need is a cash back credit card instead of earning miles on an airline-affiliated credit card. Our favorite is the Blue Cash Card from American Express. After you reach $6500 or more charged on the card, you'll get 5% cash back on grocery, gas station, and drugstore purchases, and 1.25% on everything else. So let's say you spend $5000 on those 5% categories. You'll get $250 back, which these days is enough to fly you coast to coast. Charge the same $5000 on your United Visa, and you're only 1/5 of the way towards a free ticket. It just makes sense to go for the cash, at least for most people. Of course, if you're saving up miles for a free business class upgrade or an expensive international ticket, then maybe you want to collect as many miles as possible. But if you normally fly coach domestically, we think the cash back card is the way to go.